Drug Groups

approved; investigational

Description

Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) for the treatment of HIV infection in adults. Emtricitabine is an analogue of cytidine. The drug works by inhibiting reverse transcriptase, the enzyme that copies HIV RNA into new viral DNA.

Indication

Indicated, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults and for postexposure prophylaxis of HIV infection in health care workers and others exposed occupationally or nonoccupationally via percutaneous injury or mucous membrane or nonintact skin contact with blood, tissues, or other body fluids associated with risk for transmission of the virus.

Pharmacology

Emtricitabine is a nucleoside reverse transcriptase inhibitor (NRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Emtricitabine helps to block HIV reverse transcriptase, a chemical in your body (enzyme) that is needed for HIV to multiply. Emtricitabine is always used with other anti-HIV medicines to treat people with HIV infection. Emtricitabine may lower the amount of HIV in the blood (viral load). Emtricitabine may also help to increase the number of T cells called CD4 cells. Lowering the amount of HIV in the blood lowers the chance of death or infections that happen when your immune system is weak (opportunistic infections). People taking emtricitabine may still get opportunistic infections or other conditions that happen with HIV infection.

Toxicity

Symptoms of overdose include serious liver problems (hepatotoxicity, with liver enlargement and fat in the liver called steatosis) or a lactic acidosis (buildup of an acid in the blood).

Affected Organisms

Biotransformation

Minimally transformed (13%), most appears unchanged in urine (86%). The biotransformation of emtricitabine includes oxidation of the thiol moiety to form the 3′-sulfoxide diastereomers (~ 9% of dose) and conjugation with glucuronic acid to form 2′-O-glucuronide (~ 4% of dose). In vitro studies indicate emtricitabine is not an inhibitor or cytochrome P450 enzymes.

Absorption

Rapidly absorbed (mean absolute bioavailability of 93% for capsules, and 75% for solution). Food does not effect absorption.

Half Life

10 hours

Protein Binding

Very low (less than 4%)

Elimination

The renal clearance of emtricitabine is greater than the estimated creatinine clearance, suggesting elimination by both glomerular filtration and active tubular secretion.

Clearance

* 302 +/- 94 mL/min [Renal Function Creatinine Clearance>80 ml/min]
* 168 +/- 10 mL/min [Renal Function Creatinine Clearance 50-80 ml/min]
* 138 +/- 28 mL/min [Renal Function Creatinine Clearance 30-49 ml/min]
* 99 +/- 6 mL/min [Renal Function Creatinine Clearance<30 ml/min]
* 64 +/- 12 mL/min [ESRD patients requiring dialysis]

References

External Links